Two unknown daylight lights observed high above DenverWhile picking up mail at a downtown Denver post office I glanced up and saw two bright white oval lights high in the sky above Denver. They were slightly to the west, about 5 to 7 degrees to the west and slightly south of the east-west axis of nearby Colfax Avenue.At first I thought they were planes but were not moving as planes would, almost stationary. I pointed out the high unknowns to a postal worker and two other regulars who pick up mail at the p.o. back door. Over the next few minutes we were busy receiving mail and kibitzing, but periodially looked up at the unknowns. One observer thought they were balloons. Their height was undetermined but some observers saw a plane in the vicinity (no contrail) which seemed to disappear as it apparently lost an angle for reflecting its image from the sun in the east.Over the next few minutes the lights seemed to move closer together and more easterly (closer to being directly overhead, but still a few degrees to the west). At about 9:08 a.m. when we looked up one of the lights had disappeared and other was a few degrees more to the south. When we looked up around 9:10 a.m. the second bright circular light had disappeared.The FAA in Washington was contacted about 1 p.m. by me and I was referred to the Denver FAA office. The "watch officer" I was referred to said no one else had reported anything unusual ove Denver air space. He was unaware of any balloon launches. (I had earlier contacted someone I know at the Weather Service and they said their balloons are launched hours earlier and expressed doubt the objects observed were theirs). The Weather Service said if their balloons "pop" the instruments descend by parachute. No parachutes were observed after the bright lights dsappeared.The NUFORC was contacted (which the Washington FAA office had suggested as a second contact number) and I was asked if I knew of wind direction and force aloft over Denver at 0900 It was suggested the Denver FAA office would have that info. I contacted the Denver FAA office a second time to try and obtain this information as it wuld help determine if the unknows were balloons - but my second transfer to the watch officer was answered by automatic voice mail. So I referred to my earlier call, apologized if I was being a nuisance, and asked for wind directions and force for three elevations above ground level and left my work number. As of 18:30 MST my call had not been returned. (I now know more about what to ask for when initially contacting the FAA).This sighting could have been the launch of two balloons by unknown researchers but until wind conditions are determined this sighting will be inconclusive.